docs: def _set_mappings(self):
          """ Set command mappings according to rTorrent version.
          """
          try:
              self._versions = (self.system.client_version(), self.system.library_version(),)
              self._version_info = tuple(int(i) for i in self._versions[0].split('.'))
              self._use_deprecated = self._version_info < (0, 8, 7)
  
              # Merge mappings for this version
              self._mapping = self._mapping.copy()
              for key, val in sorted(i for i in vars(config).items() if i[0].startswith("xmlrpc_")):
                  map_version = tuple(int(i) for i in key.split('_')[1:])
                  if map_version <= self._version_info:
                      if config.debug:
                          self.LOG.debug("MAPPING for %r added: %r" % (map_version, val))
                      self._mapping.update(val)
              self._fix_mappings()
          except ERRORS as exc:
              raise error.LoggableError("Can't connect to %s (%s)" % (self._url, exc))
  
          return self._versions, self._version_info